Journey to the Center of

the Earth

By: Jasmine JayPeriod 4

History of Pangaea

The guy who started it all was Alfred Wegener. He originated the theory of Pangaea; hethought that there was an original supercontinent 200 million years ago.

Unfortunately, the theory of Pangaea was not at first accepted by scientists. Manyscientists felt this way because the actual forces generated by the rotation of the Earthwere calculated to be insufficient to move continents.

Pangaea means “Super Earth & All Lands,” probably because it was one giant continent.Three million years ago during the late Carboniferous period, is when Pangaea existed.

One of the other theories being discussed during the same time Wegener’s was, was called

the Contraction theory. This theory stated that the planet was once a molten ball, and in the process of cooling the surface cracked and folded up on itself.

Alfred Wegener was more than just a German geologist, he was also accomplished in thescience of Paleontology. It relates to his discoveries because it helped prove the drift theory.

Arthur Holmes, Harry Hess, and R. Dietz all assisted in therecognition of Wegener’s theory. The ideas that these people related to Alfred’s theories were the hypothesis about the mantle under going thermal convection, Mid-Atlantic ridges being parallel to mid-oceanic ridges, and the association of islandarcs and oceanic trenches occurring together and near the continental margins.

Convergent BoundariesTo start you off your journey of learning about Plate Tectonics, I’ll tell you about

Convergent Boundaries. A Convergent Boundary is when two plate tectonics collide, causing

one to be forced under the other. Mountains (a natural elevation of the Earth’s surface,

usually higher than 2,000ft) form when this happens by land. This collision can also cause

volcanoes (a vent in the Earth’s crust, which lava, ashes, and steam come out; usually at

irregular intervals)to form and earthquakes (is the result of a sudden release of energy in the

Earth's crust that creates seismic waves) to occur. Several natural disasters can be a result of a convergent boundary. They are volcanoes,

earthquakes, mountains, landslides(a mass of soil or rock falling downward on a steep slope), mudslides (a heap of mud rapidly moving downward), and avalanches.

One example of this is the Himalayas which is where two continental plates collided. The two plates involved were the India and Eurasia plates.

Divergent BoundariesAnother important part of plate tectonics are Divergent Boundaries. A Divergent

Boundary is a linear feature that exists between two tectonic plates that are movingaway from each other. When this happens, it occurs above rising convection currents.Rising currents push up on the bottom of the lithosphere, causing lifting and flowingbeneath it. This lateral fall causes plate material above to be dragged along in thedirection of flow. The crest of the uplift, overlying plate is stretched thin, causing it tobreak and pull apart.

Some of the hazards that are characteristics of a Divergent Boundary are volcanoesand earthquakes.

An example including the continental plates involved is the Mid-Atlantic Ridge. It’s ahigh area compared to its sea-level floor; this happens because of the lift from

convection current level. The center of

the cooling magma plug will the newly solidified material attached to the end of each plate.

Transform BoundariesThis is the final boundary (an edge between a plate that configures the Earth) I’ll

tell you about, it is called a Transform Boundary. This is when two plates (a scientific

theory which describes the large scale motions of Earth's lithosphere) slide and

grind against each other causing a fault in the plates. Some of the hazards that are characteristics of a Transform Boundary are shallow

earthquakes, faulting, and trenches (a long, narrow, deep depression in the ocean floor

that parallels a convergent boundary, involving at least one oceanic plate).A real life example of a transform boundary is the San Andreas Fault Zone of

Western North America. It connects a Divergent Boundary in the Gulf of California with

the Cascada subduction zone; it also uses a smaller number of transform faults that cut the continental lithosphere.

Real World ConnectionsNow lets learn how all this neat information ties into our world

and life. Well lets begin by learning what plate we live on. The Ancient Convergent Plate Boundary called the Appalachian Mountain Range is the plate we live on.

There are also plates that border and contain the United States, they are the North American Plate, Juan de Kuca, and thePacific plate.

Wow! Did you know that Ohio could be in serious danger because of landslide hazards?Well, we have all the tell tale signs for one; these signs are steep slopes, jointed rocks, finegrained permeable rock or sediment, clay or shale units (cause lubrication), and large amountsof water. We not only have all the materials, but we could also trigger them at any momentfor something as little as a truck driving by (causes vibration), but it doesn’t stop there. An over steepened slope or increased weight on a slope and the removal of vegetation may also cause a landslide. Not to mention there is some scary stuff happening near California, all because of the San Andreas Fault Zone. This fault zone is causing some major earthquakesaround the west of the United States, particularly hitting California.

Real World Connections continued

Ha, and you thought it stopped there. We still have more treacherous news comen’ to ya.

Ever wonder how Hawaii was made? Well, it’s a volcano chain. There are many active volcanoes

there including the most active one in the world! This volcano is called Kilauea. It all started

out with Hawaii being formed roughly in the center of the Pacific plate; because of the way it

was formed they call it a hot-spot. This means a tectonic plate is moving over a mantle plume. Now that Hawaii is created there has been many eruptions from various volcanoes, but

especially Kilauea, this is why I predict it will erupt again in the distant future.

Citations

• http://www.ucmp.berkeley.edu/geology/techist.html

• http://scign.jpl.nasa.gov/learn/plate2.htm• http://scign.jpl.nasa.gov/learn/plate6.htm• http://scign.jpl.nasa.gov/learn/plate4.htm• http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/

description_plate_tectonics.html• http://geology.com/plate-tectonics.shtml• http://www.dnr.state.oh.us/geosurvey/html/geo_f0

3/tabid/8307/Default.aspx• http://geology.com/nsta/divergent-plate-boundarie

s.shtml